Create a Policy-Based Site-to-Site VPN

Name

Enter a unique string of maximum 63 alphanumeric characters without spaces.

The string can contain colons, periods, dashes, and underscores.

Description

Enter a description containing maximum 255 characters for the VPN.

VPN profile

Select a VPN profile from the drop-down list based on the deployment scenario.

• The Inline profile is applicable only to a particular IPsec VPN. To view and edit the details, click View VPN Profile Settings on the Create VPN page.

• The Shared profile can be used by one or more IPsec VPNs. You can only view the details of the shared profiles. To view the details, click View VPN Profile Settings.

Authentication method

Select an authentication method from the list that the device uses to authenticate the source of IKE messages.

• Pre-shared based—Specifies that a pre-shared key, which is a secret key shared between the two peers, is used during authentication to identify the peers to each other. The same key must be configured for each peer.

• RSA-Signatures—Specifies that a public key algorithm, which supports encryption and digital signatures, is used.

• DSA-Signatures—Specifies that the Digital Signature Algorithm (DSA) is used.

• ECDSA-Signatures-256—Specifies that the Elliptic Curve DSA (ECDSA) using the 256-bit elliptic curve secp256r1, as specified in the Federal Information Processing Standard (FIPS) Digital Signature Standard (DSS) 186-3, is used.

• ECDSA-Signatures-384—Specifies that the ECDSA using the 384-bit elliptic curve secp384r1, as specified in the FIPS DSS 186-3, is used.

Max transmission unit

Select the maximum transmission unit (MTU) in bytes.

MTU defines the maximum size of an IP packet, including the IPsec overhead. You can specify the MTU value for the tunnel endpoint. The valid range is 68 to 9192 bytes, and the default value is 1500 bytes.

Pre-shared key

Establish a VPN connection using pre-shared keys, which is essentially a password that is same for both parties. Pre-shared keys are commonly deployed for site-to-site IPsec VPNs, either within a single organization or between different organizations.

Select the type of pre-shared key to use:

• Autogenerate—Automatically generate a unique key per tunnel.

• Manual—Enter the key manually. By default, the manual key is masked.

Pre-shared keys are applicable only if the authentication method is pre-shared based.

Devices

Add devices as endpoints in the VPN. You can add maximum two devices.

1. Click Add, and click one of the following: Device or Extranet device.

   The Add Device page opens.

2. Select the device and interface in the following fields:

   • Device—The devices list shows only physical systems.

   • External interface—Select the outgoing interface for IKE security associations (SAs). This interface is associated with a zone that acts as its carrier, providing firewall security for it.

3. Click OK.

Device

Select a device.

External interface

Select the outgoing interface for IKE security associations (SAs).

This interface is associated with a zone that acts as its carrier, providing firewall security for it.

IKE Settings

Authentication method

Select an authentication method from the list that the device uses to authenticate the source of IKE messages.

• Pre-shared based—Specifies that a pre-shared key, which is a secret key shared between the two peers, is used during authentication to identify the peers to each other. The same key must be configured for each peer.

• RSA-Signatures—Specifies that a public key algorithm, which supports encryption and digital signatures, is used.

• DSA-Signatures—Specifies that the Digital Signature Algorithm (DSA) is used.

• ECDSA-Signatures-256—Specifies that the Elliptic Curve DSA (ECDSA) using the 256-bit elliptic curve secp256r1, as specified in the Federal Information Processing Standard (FIPS) Digital Signature Standard (DSS) 186-3, is used.

• ECDSA-Signatures-384—Specifies that the ECDSA using the 384-bit elliptic curve secp384r1, as specified in the FIPS DSS 186-3, is used.

IKE version

Select the V1 IKE version which is used to negotiate dynamic security associations (SAs) for IPsec.

Mode

Select an IKE policy mode.

• Main—Uses six messages in three peer-to-peer exchanges to establish the IKE SA. These three steps include the IKE SA negotiation, a Diffie-Hellman exchange, and authentication of the peer. This mode provides identity protection.

• Aggressive—Takes half the number of messages of main mode, has less negotiation power, and does not provide identity protection.

Mode is applicable when the IKE Version is V1.

Encryption algorithm

Select the appropriate encryption mechanism.

Authentication algorithm

Select an algorithm.

The device uses this algorithm to verify the authenticity and integrity of a packet.

Deffie Hellman group

Select a group.

Diffie-Hellman (DH) groups determine the strength of the key used in the key exchange process.

Lifetime seconds

Select a lifetime of an IKE security association (SA) in seconds.

The valid range is from 180 to 86400 seconds.

Dead peer detection

Enable this option to permit the two gateways to determine if the peer gateway is up and responding to the Dead Peer Detection (DPD) messages that are negotiated during IPsec establishment.

DPD mode

Select a DPD Mode.

• Optimized: R-U-THERE messages are triggered if there is no incoming IKE or IPsec traffic within a configured interval after the device sends outgoing packets to the peer. This is the default mode.

• Probe Idle Tunnel: R-U-THERE messages are triggered if there is no incoming or outgoing IKE or IPsec traffic within a configured interval. R-U-THERE messages are sent periodically to the peer until there is traffic activity.

• Always-send: R-U-THERE messages are sent at configured intervals regardless of traffic activity between the peers.

DPD interval

Select an interval in seconds to send dead peer detection messages.

The default interval is 10 seconds with a valid range of 2 to 60 seconds.

DPD threshold

Select the failure DPD threshold value.

This specifies the maximum number of times the DPD messages must be sent when there is no response from the peer. The default number of transmissions is 5 times with a valid range of 1 to 5.

Advanced Configuration

General IKE ID

Enable this option to accept peer IKE ID.

This option is disabled by default. If General IKE ID is enabled, the IKE ID option is disabled automatically.

IKE ID

Select one of the following options:

• None

• Distinguished name

• Hostname

• IPv4 address

• E-mail Address

IKE ID is applicable only when General IKE ID is disabled.

NAT-T

Enable Network Address Translation-Traversal (NAT-T) if the dynamic endpoint is behind a NAT device.

Keep alive

Select a period in seconds to keep the connection alive.

NAT Keepalives are required to maintain the NAT translation during the connection between the VPN peers. The valid range is from 1 to 300 seconds.

IPSec Settings

Protocol

Select the required protocol to establish the VPN.

• ESP—The Encapsulating Security Payload (ESP) protocol provides both encryption and authentication.

• AH—The Authentication Header (AH) protocol provides data integrity and data authentication.

Encryption algorithm

Select the encryption method.

This option is applicable if the Protocol is ESP.

Authentication algorithm

Select an algorithm.

The device uses these algorithms to verify the authenticity and integrity of a packet.

Perfect forward secrecy

Select Perfect Forward Secrecy (PFS) as the method that the device uses to generate the encryption key.

The PFS generates each new encryption key independently from the previous key. The higher numbered groups provide more security but require more processing time.

Establish tunnel

Select an option to specify when IKE is activated.

• Immediately—IKE is activated immediately after VPN configuration changes are committed.

• On-traffic—IKE is activated only when data traffic flows and must be negotiated with the peer gateway. This is the default behavior.

Advanced Configuration

VPN monitor

Enable this option to send Internet Control Message Protocol (ICMP) to determine if the VPN is up.

Optimized

Enable this option to optimize VPN monitoring and configure SRX Series Firewalls to send ICMP echo requests, also called pings, only when there is outgoing traffic and no incoming traffic from the configured peer through the VPN tunnel.

If there is incoming traffic through the VPN tunnel, the SRX Series Firewalls considers the tunnel to be active and do not send pings to the peer.

Anti replay

Enable this option for the IPsec mechanism to protect against a VPN attack that uses a sequence of numbers that are built into the IPsec packet.

IPsec does not accept a packet for which it has already seen the same sequence number. It checks the sequence numbers and enforces the check rather than just ignoring the sequence numbers.

Disable this option if there is an error with the IPsec mechanism that results in out-of-order packets, preventing proper functionality.

By default, Anti replay detection is enabled.

Install interval

Select the maximum number of seconds to allow for the installation of a re-keyed outbound security association (SA) on the device.

Idle time

Select the appropriate idle time interval.

The sessions and their corresponding translations typically time out after a certain period if no traffic is received.

DF bit

Select an option to process the Don’t Fragment (DF) bit in IP messages.

• Clear—Disable the DF bit from the IP messages. This is the default option.

• Copy—Copy the DF bit to the IP messages.

• Set—Enable the DF bit in the IP messages.

Copy outer DSCP

Enable this option to allow copying of the Differentiated Services Code Point (DSCP) field from the outer IP header encrypted packet to the inner IP header plain text message on the decryption path.

The benefit in enabling this option is that after IPsec decryption, clear text packets can follow the inner class-of-service (CoS) rules.

Lifetime seconds

Select a lifetime of an IKE security association (SA) in seconds.

The valid range is from 180 to 86,400 seconds.

Lifetime kilobytes

Select the lifetime of an IPsec security association (SA) in kilobytes.

The range is from 64 to 4294967294 kilobytes.